1. Field of the Invention
The present invention relates to bursting machines for continuous, perforated strips which are typically provided from computers as printed output documents in fan-folded form.
There is a tremendous amount of printed material generated by computers, and the material is substantially growing as the use of computers grows. Correspondingly, there is a great variety of type and size of continuous perforated strips which must be processed through a bursting machine in order to separate the individual sheets from the strip.
In particular, there is a great variation in respect to the lineal length dimension of the discrete sheet between perforations. The length variation requires that a bursting machine be adjusted to compensate for the changing position of the perforation line in the path of travel of the strip of sheets being conveyed through the bursting machine. To date, the requirement of the adjustment described, and the manner for accomplishing the adjustment is time consuming, awkward and creates a potential for making errors.
2. Description of the Prior Art
The earliest forms of bursting machines representing the prior art have typically been adapted to handle continuous, perforated strips wherein there was known but one length of sheet. There was no requirement therefore to adjust a bursting machine for alternate sheet lengths because of alternate supplies of perforated strips. As more use of computers evolved however, there was an increase in varying lengths of the sheets within the strip depending on the requirements of public serving companies requiring billing material for customers and other computer printout data of varying scope and complexity.
Eventually, bursting machines evolved having a mechanical adjusting apparatus built into the machine which required an operator to take certain steps to accommodate the material to be burst. The steps did not include reference to a gauge or similar guide to make the task easier.
Still later versions of bursting machines are adjustable, and do provide a gauge which is referred to by the operator when determining where the strip is to be burst. Typically however, the gauge is utilized in combination with the adjustment and is accomplished by moving at least one pair of feed rollers which carries the continuous strip. This is a relatively awkward, time consuming and cumbersome task for an operator, which leaves a problem still unsolved until the present invention.
3. The Prior Art
U.S. Pat. No. 3,481,520, issued to Pickering on Dec. 2, 1969, discloses a process and apparatus for severing sheets of uniform lengths from a moving web of material. The patent discusses use of a preset counter and a cooperating pulse generator to measure off the desired length of a separate sheet. However, there is no apparatus or description provided as to how to preset the counter to accommodate a continuous perforated strip. In addition, it is required that the strip be severed, thereby adding apparatus to the machine, which is unnecessary with the present day use of perforated strips that are easily torn apart.
Another issued patent, U.S. Pat. No. 4,025,023 to Moffitt on May 24, 1977 relates to a bursting machine having the second feeding means operable to a faster rate than the first. The increased speed of the second feeding rollers is faster than the strips predetermined speed, and is applied at a time controlled by activation of those rollers by a signal from a central device. While there is no adjustment of the roller spacing described, it is implied that a push button on a control panel be used to accommodate different sheet lengths. However, there is no accompanying apparatus, description nor procedure provided to implement the idea.
Yet another U.S. Patent, U.S. Pat. No. 4,284,221 to Nagel et al on Aug. 18, 1981, discloses a bursting machine which utilizes a counter for transmitting actuating signals at regular intervals when feeding a web at constant speed. The web has sheets of equal lengths, and there is a sheet length measuring device mentioned, but not shown or described. Again, to the extent that this subject is mentioned, it is entirely unclear how the length measuring device is constructed or utilized. Therefore, the problem of providing an "operator friendly" system to accommodate varying sheet lengths within different continuous perforated strips has remained unsolved until the present invention.